Third rail cover board

ABSTRACT

An electrically insulative cover board is elongated in the direction of the longitudinal axis of an electrified third rail and includes a top wall having a lateral cross sectional shape which is arcuate with the concavity thereof facing the top of the third rail and a side wall contiguous with the top wall. The side wall includes a plurality of generally upstanding portions, a plurality of arcuate portions with the convexity of each facing the side of the third rail and positioned between the upstanding portions, and a plurality of supportive wall portions each extending from a respective edge of a respective arcuate portion to the edge of a respective one of the upstanding portions. Each arcuate portion of the side wall is attached to the third rail by a clip member. The clip member has a configuration such that the distance from its point of attachment to the arcuate portion of the cover board to an adjacent flange of the third rail is optimally minimal.

United States Patent [191 Reynolds et al.

[ THIRD RAIL COVER BOARD [76] inventors: Clarke Reynolds, 535 Hillary Drive,

Tiburon, Calif. 94920; Richard J. Quigley, 2221 Via Maderos, Los Altos, Calif. 94022 [22] Filed: Oct. 23, 1974 [21] Appl. No.: 517,081

Primary ExaminerM. H. Wood, Jr. Assistant Examiner-Richard A. Bertsch Attorney, Agent, or FirmLowhurst & Aine Dec. 23, 1975 [57] ABSTRACT An electrically insulative cover board is elongated in the direction of the longitudinal axis of an electrified third rail and includes a top wall having a lateral cross sectional shape which is arcuate with the concavity thereof facing the top of the third rail and a side wall contiguous with the top wall. The side wall includes a plurality of generally upstanding portions, a plurality of arcuate portions with the convexity of each facing the side of the third rail and positioned between the upstanding portions, and a plurality of supportive wall portions each extending from a respective edge of a respective arcuate portion to the edge of a respective one of the upstanding portions. Each arcuate portion of the side wall is attached to the third rail by a clip member. The clip member has a configuration such that the distance from its point of attachment to the arcuate portion of the cover board to an adjacent flange of the third rail is optimally minimal.-

7 Claims, 4 Drawing Figures US. Patent Dec.23, 1975 Sheet10f2 3,927,742

U.S. Patent Dec.23, 1975 Sheet20f2 3,927,742

THIRD RAIL COVER BOARD BACKGROUND OF THE INVENTION such a rail and has the same lateral cross sectional.

shape along its entire length. The upstanding side wall of this rail cover board includes a longitudinally directed, laterally protruding convolution and the inside side wall of the cover is open to allow a traveling electrical contactor to make electrical contact with the third rail. Because of this configuration, the bracket which is employed to secure the cover board onto the third rail is relatively large, extending from an adjacent flange of the rail to the inside side wall of the cover.

That is, the bracket for securing the cover board onto the third rail is relatively large and extends a considerable lateral distance from the rail to the cover board. This lateral span permits the bracket to be subjected to stress at certain localized points thereon under loaded conditions.

In order to reduce the weight and cost of such a bracket, it is provided with a void, such that it is not solid in a lateral cross section therethrough and is not continuous from its point of attachment to the cover board to its contact with the rail surface. Such a void or discontinuity in the lateral cross sectional shape of the bracket permits the material of the bracket at the above mentioned stress points to rupture under loaded conditions.

Because of the unusual shape required for such brackets, it has been necessary in the past to mold such brackets from a suitable material, such as fiberglass. However, because of the relatively loose tolerances required of hot rolled track rails, such materials, including fiberglass, have been unsuitable, since they do not conform to the shape of the rail. Accordingly, additional stress points are created on the bracket because of its inability to conform to the shape of the third rail to which it is attached and such stress points are also subject to rupture. Rupture of such a bracket can be overcome under normal loaded conditions thereon if a sufficient amount of material is provided in the fabrication of the bracket. However, such additional material increases its weight and cost considerably.

It has also been found that the cover board disclosed in the above mentioned patent is not capable of transferring the majority of the forces imposed thereon under loaded conditions to the attaching bracket. On the contrary, the majority of these forces cause the cover board to deflect around a longitudinal line which is located at the intersection of the side wall of the board with the upper most portion of the bracket. Such flexure along this line may also result in rupture of the cover board.

SUMMARY OF THE INVENTION It is, therefore, an object of the present invention to provide a cover board for an electrified third rail and a bracket for securing the cover board to the rail in which a substantial portion of the forces existing under loaded conditions are transferred from the cover to the bracket.

Another object of the present invention is to provide a cover board for an electrified third rail and a bracket for attaching the cover board to the third rail in which a portion of the cover board extends toward and is in close proximity to the third rail at its point of attachment to the bracket, such that the bracket is of minimum size.

Still another object of the present invention is to provide a cover board for an electrified third rail and a bracket for attaching the cover board to the rail in which stress points are considerable reduced in comparison to the number of stress points existing in prior known cover boards and brackets.

A further object of the present invention is to provide a cover board for an electrified third rail and a bracket for attaching such a board to the third rail in which a portion of the function of prior known cover board brackets is performed by a portion of the cover board, such that a relatively small and inexpensive bracket can be employed.

Still a further object of the present invention is to provide a cover board for an electrified third rail and a bracket for attaching the cover board to the rail in which the bracket forms an extension of the rail by being absent of any voids therein.

These and other objects of the present invention are attained by an electically insulative cover board having a side wall which includes at least a pair of generally upstanding portions, an arcuate portion with its convexity facing the side of the electrified third rail and located between the upstanding portions, and a pair of supportive wall portions each extending from a respective edge of the arcuate portion to the edge of a respective one of the upstanding portions, and means for attaching the arcuate portion to the electrified third rail. 7

A feature of the present invention resides in the provision of a bracket for attaching the arcuate portion to the third rail which is absent of any voids and in which the distance from its point of attachment to the arcuate portion to an adjacent flange of the third rail is optimally minimal.

The cover board of the present invention has the distinct advantage of spreading the forces generated by an external load thereon and transferring the majority of such forces through the supportive wall portions thereof to the associated bracket, such that isolated stress points are not formed on either the cover board or the bracket.

The present invention also has the advantage that a relatively small bracket can be employed, thereby reducing its weight and cost in comparison to prior known cover board brackets.

These and other objects, features and advantages of the present invention, however, will be more fully realized and understood from the following detailed description, when taken in conjunction with the accompanying drawings, wherein:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view in perspective, partially in section and partially broken away of an electrically insulative cover board and bracket constructed in accordance with the principles of the present invention and illustrated as being mounted on an electrified third rail.

FIG. 2 is an end view, partially in section, of the cover board, bracket and rail illustrated in FIG. 1.

FIG. 3 is a sectional view taken generally along line 33 of FIG. 2.

FIG. 4 is a sectional view taken generally along line 4-4 of FIG. 3. I

Like reference numerals throughout the various views of the drawings are intended to designate the same elements.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT With reference to the drawings in detail, there is shown an electrically insulative cover board which is constructed in accordance with the principles of the present invention and is generally designated with the reference numeral 10. The cover board may be formed of any suitable insulative material, such as fiberglass. The board 10 is intended to cover an electrified third rail 12 of a track system and to protect the rail 12 from relatively high impact vertical loads. The cover board 10 includes a top wall 14 having a lateral cross sectional shape which is arcuate with the concavity thereof facing the top of the rail 12. A side wall, generally designated with the reference numeral 16, is contiguous with the top wall 14. The side wall 16 includes a plurality of upstanding portions, one of which is shown in FIG. 1 and designated with the reference numeral 18. The side wall 16 also includes a plurality of arcuate portions at spaced locations along the length of .the board 10, one of which is shown in FIG. 1 and designated with the reference numeral 20. A pair of supportive wall portions 22 and 24 (see FIG. 3) extend between repective edges of the arcuate portion and the upstanding portions 18. Each arcuate portion 20 is formed of a pair of walls 26 and 28 which are substantially flat and intersect one another. The side wall 16 also includes a pair of longitudinally extending convolutions 30 and 32 which tend to reduce lateral bowing of the cover board when it is subjected to an external load.

A clip member or bracket, generally designated with the reference numeral 34 includes a first retaining flange member 36 which is disposed for engaging a bottom surface of the rail 12 and for gripping a lower flange 38 of the rail. The clip member 34 also includes a second retaining flange member 40 which is disposed for engaging lower flange 42 of the rail 12. Retaining members 36 and 40 are secured together by a bolt 44 and nut 46.

Retaining member 40 is provided with a plate 48 which forms an upper surface portion for receiving the wall 28 of the arcuate protion 20. A plate 50 is mounted on the opposite side of the wall 28 and a bolt 52, of Nylon material for example, extends through the plate 50 and the wall 28 and is threaded into an appropriate hole in the retaining member 40.

It can be appreciated from the drawings that the point of attachment of the board 10 to the retaining member 40 is a relatively small and optimally minimal distance from an adjacent edge of the rail 12. In this respect, the clip member 34 effectively forms an extension of the rail 12. It has been the practice, as exemplified by the device disclosed in US. Pat. No. 3,806,672, to form the cover board with the same cross sectional shape along its entire length and to provide a bracket which spans the gap between an edge of the rail and an inner surface of the side wall of the board. This gap between the side wall of the cover board and the rail is required because of the possibility of an object falling on the rail and becoming lodged between the side wall and the top of the rail. However, this gap need only exist between adjacent brackets along the length of the rail. The cover board of the present invention fulfills that function, which was previously fulfilled by the bracket, by the provision of the arcuate portion 20 which extends toward the rail and is relatively narrow in comparison to the distance between adjacent brackets.

Because of the relatively large gap which was spanned by the prior known brackets, their strength was either reduced or they were relatively heavy and costly. That is, if a relatively light weight and inexpensive bracket was to be employed in the past, voids were required in its structure, thereby reducing its strength and increasing its susceptibility to rupture due to localized stress points. It can be appreciated from the drawings that the clip member 34 of the present invention is relatively small, effectively forming an extension of the rail 12, thereby reducing its weight and cost in comparison to prior known brackets.

When a vertical load is imposed on the top wall 14, the forces generated within the cover board 10 will be transferred toward the bracket 34. It can be appreciated from the drawings that these forces will spread through and be carried by walls 22, 24 and 26 to the bracket 34. It will also be appreciated that relatively little deflection will occur at the junction of the walls 26 and 28, which is the upper most line of support offered by the bracket 34. However, in prior known cover board structures, the majority of the deflection of a cover board occurred around the upper most line of support between the bracket and the cover board. As a result of this configuration, the cover board was highly susceptible to rupture along such a line. However, the cover board of the present invention, by spreading the forces through the walls 22, 24 and 26 considerably reduces the possibility of rupture occurring along a line or maximum deflection of the cover board. In the cover board of the present invention, this line of maximum deflection is in the vicinity of the convolution 30.

It can be appreciated from the above that by the provision of the arcuate portion 30 several distinct advantages are realized. More particularly, the weight and cost of the bracket 34 can be reduced considerably over that of prior known brackets. Also, the possibility of rupture of either the bracket or the cover board is considerably reduced. It follows, therefore, that the strength of the bracket and cover board are increased by the provision of the arcuate portion 20, thereby increasing the allowable limits of a vertical load which can be imposed on the cover board 10.

The invention claimed is:

1. A cover for an electrified third rail, comprising a. an electrically insulative cover board which is elongated in the direction of the longitudinal axis of such a rail and includes a top wall having a lateral cross sectional shape which is arcuate with the concavity thereof facing the top of such a rail and a side wall contiguous with said top wall; said side wall including 1. a pair of generally upstanding portions,

2. an arcuate portion with the convexity thereof facing the side of such a rail and located between said upstanding portions, and

3. a pair of supportive wall portions each extending from a respective edge of said arcuate portion to the edge of a respective one of said upstanding portions; and

b. means for attaching said arcuate portion to such a rail.

2. The cover of claim 1, wherein said arcuate portion includes a pair of walls extending in intersecting relationship to one another, said attaching means includes a first clip member disposed for gripping a respective lower flange of such a rail, and a fastener extending between one of said pair of walls of said arcuate portion and said first clip member.

3. The cover of claim 2, wherein said first clip member includes a retaining flange disposed for gripping the respective lower flange of the rail and an upper surface portion integral with and extending directly from said retaining flange, said one of said pair of walls of said 6 arcuate portion being conformably shaped to and engaging said upper surface portion.

4. The cover of claim 3, wherein said first clip member is solid from its point of engagement with an edge of a flange of the rail to said fastener.

5. The cover of claim 3, wherein the point of engagement of said first clip member with an edge of a flange of the rail is adjacent to said fastener.

6. The cover of claim 2, wherein the point of engagement of said first clip member with an edge of a flange of the rail is adjacent to said fastener.

7. The cover of claim 6, wherein said attaching means includes a second clip member disposed for gripping a respective lower flange of the rail and means for securing said first clip member to said second clip member. 

1. A cover for an electrified third rail, comprising a. an electrically insulative cover board which is elongated in the direction of the longitudinal axis of such a rail and includes a top wall having a lateral cross sectional shape which is arcuate with the concavity thereof facing the top of such a rail and a side wall contiguous with said top wall; said side wall including
 1. a pair of generally upstanding portions,
 2. an arcuate portion with the convexity thereof facing the side of such a rail and located between said upstanding portions, and
 3. a pair of supportive wall portions each extending from a respective edge of said arcuate portion to the edge of a respective one of said upstanding portions; and b. means for attaching said arcuate portion to such a rail.
 2. an arcuate portion with the convexity thereof facing the side of such a rail and located between said upstanding portions, and
 2. The cover of claim 1, wherein said arcuate portion includes a pair of walls extending in intersecting relationship to one another, said attaching means includes a first clip member disposed for gripping a respective lower flange of such a rail, and a fastener extending between one of said pair of walls of said arcuate portion and said first clip member.
 3. The cover of claim 2, wherein said first clip member includes a retaining flange disposed for gripping the respective lower flange of the rail and an upper surface portion integral with and extending directly from said retaining flange, said one of said pair of walls of said arcuate portion being conformably shaped to and engaging said upper surface portion.
 3. a pair of supportive wall portions each extending from a respective edge of said arcuate portion to the edge of a respective one of said upstanding portions; and b. means for attaching said arcuate portion to such a rail.
 4. The cover of claim 3, wherein said first clip member is solid from its point of engagement with an edge of a flange of the rail to said fastener.
 5. The cover of claim 3, wherein the point of engagement of said first clip member with an edge of a flange of the rail is adjacent to said fastener.
 6. The cover of claim 2, wherein the point of engagement of said first clip member with an edge of a flange of the rail is adjacent to said fastener.
 7. The cover of claim 6, wherein said attaching means includes a second clip member disposed for gripping a respective lower flange of the rail and means for securing said first clip member to said second clip member. 